class AliasManager in Zircon Profile 8

The default alias manager implementation.

Hierarchy

• class \Drupal\Core\Path\AliasManager implements CacheDecoratorInterface, AliasManagerInterface

2 files declare their use of AliasManager

AliasManagerTest.php in core/tests/Drupal/Tests/Core/Path/AliasManagerTest.php

Contains \Drupal\Tests\Core\Path\AliasManagerTest.

AliasTest.php in core/modules/system/src/Tests/Path/AliasTest.php

Contains \Drupal\system\Tests\Path\AliasTest.

1 string reference to 'AliasManager'

core.services.yml in core/core.services.yml

core/core.services.yml

1 service uses AliasManager

path.alias_manager in core/core.services.yml

Drupal\Core\Path\AliasManager

File

core/lib/Drupal/Core/Path/AliasManager.php, line 18

Contains \Drupal\Core\Path\AliasManager.

Namespace

Drupal\Core\Path

class AliasManager implements AliasManagerInterface, CacheDecoratorInterface {

  /**
   * The alias storage service.
   *
   * @var \Drupal\Core\Path\AliasStorageInterface
   */
  protected $storage;

  /**
   * Cache backend service.
   *
   * @var \Drupal\Core\Cache\CacheBackendInterface;
   */
  protected $cache;

  /**
   * The cache key to use when caching paths.
   *
   * @var string
   */
  protected $cacheKey;

  /**
   * Whether the cache needs to be written.
   *
   * @var bool
   */
  protected $cacheNeedsWriting = FALSE;

  /**
   * Language manager for retrieving the default langcode when none is specified.
   *
   * @var \Drupal\Core\Language\LanguageManagerInterface
   */
  protected $languageManager;

  /**
   * Holds the map of path lookups per language.
   *
   * @var array
   */
  protected $lookupMap = array();

  /**
   * Holds an array of aliases for which no path was found.
   *
   * @var array
   */
  protected $noPath = array();

  /**
   * Holds the array of whitelisted path aliases.
   *
   * @var \Drupal\Core\Path\AliasWhitelistInterface
   */
  protected $whitelist;

  /**
   * Holds an array of paths that have no alias.
   *
   * @var array
   */
  protected $noAlias = array();

  /**
   * Whether preloaded path lookups has already been loaded.
   *
   * @var array
   */
  protected $langcodePreloaded = array();

  /**
   * Holds an array of previously looked up paths for the current request path.
   *
   * This will only get populated if a cache key has been set, which for example
   * happens if the alias manager is used in the context of a request.
   *
   * @var array
   */
  protected $preloadedPathLookups = FALSE;

  /**
   * Constructs an AliasManager.
   *
   * @param \Drupal\Core\Path\AliasStorageInterface $storage
   *   The alias storage service.
   * @param \Drupal\Core\Path\AliasWhitelistInterface $whitelist
   *   The whitelist implementation to use.
   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
   *   The language manager.
   * @param \Drupal\Core\Cache\CacheBackendInterface $cache
   *   Cache backend.
   */
  public function __construct(AliasStorageInterface $storage, AliasWhitelistInterface $whitelist, LanguageManagerInterface $language_manager, CacheBackendInterface $cache) {
    $this->storage = $storage;
    $this->languageManager = $language_manager;
    $this->whitelist = $whitelist;
    $this->cache = $cache;
  }

  /**
   * {@inheritdoc}
   */
  public function setCacheKey($key) {

    // Prefix the cache key to avoid clashes with other caches.
    $this->cacheKey = 'preload-paths:' . $key;
  }

  /**
   * {@inheritdoc}
   *
   * Cache an array of the paths available on each page. We assume that aliases
   * will be needed for the majority of these paths during subsequent requests,
   * and load them in a single query during path alias lookup.
   */
  public function writeCache() {

    // Check if the paths for this page were loaded from cache in this request
    // to avoid writing to cache on every request.
    if ($this->cacheNeedsWriting && !empty($this->cacheKey)) {

      // Start with the preloaded path lookups, so that cached entries for other
      // languages will not be lost.
      $path_lookups = $this->preloadedPathLookups ?: array();
      foreach ($this->lookupMap as $langcode => $lookups) {
        $path_lookups[$langcode] = array_keys($lookups);
        if (!empty($this->noAlias[$langcode])) {
          $path_lookups[$langcode] = array_merge($path_lookups[$langcode], array_keys($this->noAlias[$langcode]));
        }
      }
      $twenty_four_hours = 60 * 60 * 24;
      $this->cache
        ->set($this->cacheKey, $path_lookups, $this
        ->getRequestTime() + $twenty_four_hours);
    }
  }

  /**
   * {@inheritdoc}
   */
  public function getPathByAlias($alias, $langcode = NULL) {

    // If no language is explicitly specified we default to the current URL
    // language. If we used a language different from the one conveyed by the
    // requested URL, we might end up being unable to check if there is a path
    // alias matching the URL path.
    $langcode = $langcode ?: $this->languageManager
      ->getCurrentLanguage(LanguageInterface::TYPE_URL)
      ->getId();

    // If we already know that there are no paths for this alias simply return.
    if (empty($alias) || !empty($this->noPath[$langcode][$alias])) {
      return $alias;
    }

    // Look for the alias within the cached map.
    if (isset($this->lookupMap[$langcode]) && ($path = array_search($alias, $this->lookupMap[$langcode]))) {
      return $path;
    }

    // Look for path in storage.
    if ($path = $this->storage
      ->lookupPathSource($alias, $langcode)) {
      $this->lookupMap[$langcode][$path] = $alias;
      return $path;
    }

    // We can't record anything into $this->lookupMap because we didn't find any
    // paths for this alias. Thus cache to $this->noPath.
    $this->noPath[$langcode][$alias] = TRUE;
    return $alias;
  }

  /**
   * {@inheritdoc}
   */
  public function getAliasByPath($path, $langcode = NULL) {
    if ($path[0] !== '/') {
      throw new \InvalidArgumentException(sprintf('Source path %s has to start with a slash.', $path));
    }

    // If no language is explicitly specified we default to the current URL
    // language. If we used a language different from the one conveyed by the
    // requested URL, we might end up being unable to check if there is a path
    // alias matching the URL path.
    $langcode = $langcode ?: $this->languageManager
      ->getCurrentLanguage(LanguageInterface::TYPE_URL)
      ->getId();

    // Check the path whitelist, if the top-level part before the first /
    // is not in the list, then there is no need to do anything further,
    // it is not in the database.
    if ($path === '/' || !$this->whitelist
      ->get(strtok(trim($path, '/'), '/'))) {
      return $path;
    }

    // During the first call to this method per language, load the expected
    // paths for the page from cache.
    if (empty($this->langcodePreloaded[$langcode])) {
      $this->langcodePreloaded[$langcode] = TRUE;
      $this->lookupMap[$langcode] = array();

      // Load the cached paths that should be used for preloading. This only
      // happens if a cache key has been set.
      if ($this->preloadedPathLookups === FALSE) {
        $this->preloadedPathLookups = array();
        if ($this->cacheKey) {
          if ($cached = $this->cache
            ->get($this->cacheKey)) {
            $this->preloadedPathLookups = $cached->data;
          }
          else {
            $this->cacheNeedsWriting = TRUE;
          }
        }
      }

      // Load paths from cache.
      if (!empty($this->preloadedPathLookups[$langcode])) {
        $this->lookupMap[$langcode] = $this->storage
          ->preloadPathAlias($this->preloadedPathLookups[$langcode], $langcode);

        // Keep a record of paths with no alias to avoid querying twice.
        $this->noAlias[$langcode] = array_flip(array_diff_key($this->preloadedPathLookups[$langcode], array_keys($this->lookupMap[$langcode])));
      }
    }

    // If we already know that there are no aliases for this path simply return.
    if (!empty($this->noAlias[$langcode][$path])) {
      return $path;
    }

    // If the alias has already been loaded, return it from static cache.
    if (isset($this->lookupMap[$langcode][$path])) {
      return $this->lookupMap[$langcode][$path];
    }

    // Try to load alias from storage.
    if ($alias = $this->storage
      ->lookupPathAlias($path, $langcode)) {
      $this->lookupMap[$langcode][$path] = $alias;
      return $alias;
    }

    // We can't record anything into $this->lookupMap because we didn't find any
    // aliases for this path. Thus cache to $this->noAlias.
    $this->noAlias[$langcode][$path] = TRUE;
    return $path;
  }

  /**
   * {@inheritdoc}
   */
  public function cacheClear($source = NULL) {
    if ($source) {
      foreach (array_keys($this->lookupMap) as $lang) {
        unset($this->lookupMap[$lang][$source]);
      }
    }
    else {
      $this->lookupMap = array();
    }
    $this->noPath = array();
    $this->noAlias = array();
    $this->langcodePreloaded = array();
    $this->preloadedPathLookups = array();
    $this->cache
      ->delete($this->cacheKey);
    $this
      ->pathAliasWhitelistRebuild($source);
  }

  /**
   * Rebuild the path alias white list.
   *
   * @param string $path
   *   An optional path for which an alias is being inserted.
   *
   * @return
   *   An array containing a white list of path aliases.
   */
  protected function pathAliasWhitelistRebuild($path = NULL) {

    // When paths are inserted, only rebuild the whitelist if the path has a top
    // level component which is not already in the whitelist.
    if (!empty($path)) {
      if ($this->whitelist
        ->get(strtok($path, '/'))) {
        return;
      }
    }
    $this->whitelist
      ->clear();
  }

  /**
   * Wrapper method for REQUEST_TIME constant.
   *
   * @return int
   */
  protected function getRequestTime() {
    return defined('REQUEST_TIME') ? REQUEST_TIME : (int) $_SERVER['REQUEST_TIME'];
  }

}

Members

Name	Modifiers	Type	Description	Overrides
AliasManager::$cache	protected	property	Cache backend service.
AliasManager::$cacheKey	protected	property	The cache key to use when caching paths.
AliasManager::$cacheNeedsWriting	protected	property	Whether the cache needs to be written.
AliasManager::$langcodePreloaded	protected	property	Whether preloaded path lookups has already been loaded.
AliasManager::$languageManager	protected	property	Language manager for retrieving the default langcode when none is specified.
AliasManager::$lookupMap	protected	property	Holds the map of path lookups per language.
AliasManager::$noAlias	protected	property	Holds an array of paths that have no alias.
AliasManager::$noPath	protected	property	Holds an array of aliases for which no path was found.
AliasManager::$preloadedPathLookups	protected	property	Holds an array of previously looked up paths for the current request path.
AliasManager::$storage	protected	property	The alias storage service.
AliasManager::$whitelist	protected	property	Holds the array of whitelisted path aliases.
AliasManager::cacheClear	public	function	Clear internal caches in alias manager. Overrides AliasManagerInterface::cacheClear
AliasManager::getAliasByPath	public	function	Given a path, return the alias. Overrides AliasManagerInterface::getAliasByPath
AliasManager::getPathByAlias	public	function	Given the alias, return the path it represents. Overrides AliasManagerInterface::getPathByAlias
AliasManager::getRequestTime	protected	function	Wrapper method for REQUEST_TIME constant.
AliasManager::pathAliasWhitelistRebuild	protected	function	Rebuild the path alias white list.
AliasManager::setCacheKey	public	function	Specify the key to use when writing the cache. Overrides CacheDecoratorInterface::setCacheKey
AliasManager::writeCache	public	function	Cache an array of the paths available on each page. We assume that aliases will be needed for the majority of these paths during subsequent requests, and load them in a single query during path alias lookup. Overrides CacheDecoratorInterface::writeCache
AliasManager::__construct	public	function	Constructs an AliasManager.